Post on 28-Dec-2015
Basic Network Concepts
Introduction to Computing Lecture#28
Overview
• Introduction to networks.• Need for networks.• Classification of networks.
Introduction to Networks • A network consists of two or more entities or objects
sharing resources and information.• A computer network consists of two or more
computing devices connected to each other to share resources and information.
• The network becomes a powerful tool when computers communicate and share resources with other computers on the same network or entirely distinct networks.
Introduction to Networks
• Computers on a network can act as a client or a server.
• A client is a computer that requests for resources.
• A server is a computer that controls and provides access to resources.
Need for Networks
A computer that operates independently from other computers is called a stand- alone computer.Need for Networks • Enhance communication.•Share resources.•Facilitate centralized management.
Enhance Communication
• Computer networks use electronic mail (e-mail) as the choice for most of the communication.
• By using networks, information can be sent to a larger audience in an extremely fast and efficient manner.
Share Resources
• A copy of data or application stored at a single
central location is shared over a network.
• Computer peripheral devices, referred to as
additional components, can be attached to a
computer and be shared in a network.
Share Resources
• Peripheral devices include faxes, printer, scanners and any other device that connects to the computers.
• Equipments having common requirements can be shared in order to reduce maintenance cost.
Facilitate Centralized Management
Software:– Software is a set of instructions or programs that
control the operation of a computer.– Software can be installed at a central location
using servers, where the installation files are made accessible over the network.
Classification of Networks
• Classification by network geography.• Classification by component roles.
Classification by NetworkGeography
• Networks are frequently classified according to the geographical boundaries spanned by the network itself.
• LAN, WAN, and MAN are the basic types of classification, of which LAN and WAN are frequently used.
Classification by NetworkGeography
Local area network (LAN):– A LAN covers a relatively small area such as a
classroom, school, or a single building.– LANs are inexpensive to install and also provide
higher speeds.
Local area network
Classification by NetworkGeography
Classification by NetworkGeography
Metropolitan area network (MAN):– A MAN spans the distance of a typical
metropolitan city.– The cost of installation and operation is higher.– MANs use high-speed connections such as fiber
optics to achieve higher speeds.
Metropolitan area network
Classification by NetworkGeography
Classification by NetworkGeography
Wide area network (WAN):– WANs span a larger area than a single city.– These use long distance telecommunication
networks for connection, thereby increasing the cost.
– The Internet is a good example of a WAN.
Wide area network
Classification by NetworkGeography
Classification by Component Roles
• Networks can also be classified according to the roles that the networked computers play in the network’s operation.
• Peer-to-peer and server-based are the types of roles, into which networks are classified.
Classification by Component Roles
Peer-to-peer:– In a peer-to-peer network, all computers are considered equal.
– Each computer controls its own information and is capable of
functioning as either a client or a server depending upon the
requirement.
– Peer-to-peer networks are inexpensive and easy to install.
– They are popular as home networks and for use in small
companies.
Classification by Component Roles
Peer-to-peer (continued):– Most operating systems come with built-in peer-
to-peer networking capability.– The maximum number of peers that can operate
on a peer-to-peer network is ten.– Each peer shares resources and allows others
open access to them.
Classification by Component Roles
Peer-to-peer (continued):– Peer-to-peer networks become difficult to
manage when more security is added to resources, since the users control their security by password-protecting shares.
– Shares can be document folders, printers, peripherals, and any other resource that they control on their computers.
Classification by Component Roles
Peer-to-peer network
Classification by Component Roles
Server-based:– A server-based network offers centralized control
and is designed for secure operations.– In a server-based network, a dedicated server
controls the network.
Classification by Component Roles
Server-based (continued):– A dedicated server is one that services the
network by storing data, applications, resources, and also provides access to resources required by the client.
– These servers can also control the network’s security from one centralized location or share it with other specially configured servers.
Classification by Component Roles
Server-based network
END